scholarly journals Cosmology with an interacting van der Waals fluid

2018 ◽  
Vol 27 (04) ◽  
pp. 1850037 ◽  
Author(s):  
E. Elizalde ◽  
M. Khurshudyan
Keyword(s):  
Dark Energy ◽  
Finite Time ◽  
Van Der Waals ◽  
The Other ◽  
Van Der Waals Fluid ◽  
Type Iv ◽  
Other Hand ◽  
The Future ◽  
Expansion Of The Universe ◽  
The Universe

A model for the late-time accelerated expansion of the Universe is considered where a van der Waals fluid interacting with matter plays the role of dark energy. The transition towards this phase in the cosmic evolution history is discussed in detail and, moreover, a complete classification of the future finite-time singularities is obtained for six different possible forms of the nongravitational interaction between dark energy (the van der Waals fluid) and dark matter. This study shows, in particular, that a Universe with a noninteracting three-parameter van der Waals fluid can evolve into a Universe characterized by a type IV (generalized sudden) singularity. On the other hand, for certain values of the parameters, exit from the accelerated expanding phase is possible in the near future, what means that the expansion of the Universe in the future could become decelerated – to our knowledge, this interesting situation is not commonplace in the literature. On the other hand, our study shows that space can be divided into different regions. For some of them, in particular, the nongravitational interactions [Formula: see text], [Formula: see text] and [Formula: see text] may completely suppress future finite-time singularity formation, for sufficiently high values of [Formula: see text]. On the other hand, for some other regions of the parameter space, the mentioned interactions would not affect the singularity type, namely the type IV singularity generated in the case of the noninteracting model would be preserved. A similar conclusion has been archived for the cases of [Formula: see text], [Formula: see text] and [Formula: see text] nongravitational interactions, with only one difference: the [Formula: see text] interaction will change the type IV singularity of the noninteracting model into a type II (the sudden) singularity.

scholarly journals Different Faces of Generalized Holographic Dark Energy

Symmetry ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 928
Author(s):  
Shin’ichi Nojiri ◽  
Sergei D. Odintsov ◽  
Tanmoy Paul
Keyword(s):  
Dark Energy ◽  
Holographic Dark Energy ◽  
Effective Equation ◽  
Eos Parameter ◽  
Particle Horizon ◽  
The Future ◽  
Expansion Of The Universe ◽  
Entropy Functions ◽  
The Universe ◽  
Future Horizon

In the formalism of generalized holographic dark energy (HDE), the holographic cut-off is generalized to depend upon LIR=LIRLp,L˙p,L¨p,⋯,Lf,L˙f,⋯,a with Lp and Lf being the particle horizon and the future horizon, respectively (moreover, a is the scale factor of the Universe). Based on such formalism, in the present paper, we show that a wide class of dark energy (DE) models can be regarded as different candidates for the generalized HDE family, with respective cut-offs. This can be thought as a symmetry between the generalized HDE and different DE models. In this regard, we considered several entropic dark energy models—such as the Tsallis entropic DE, the Rényi entropic DE, and the Sharma–Mittal entropic DE—and found that they are indeed equivalent with the generalized HDE. Such equivalence between the entropic DE and the generalized HDE is extended to the scenario where the respective exponents of the entropy functions are allowed to vary with the expansion of the Universe. Besides the entropic DE models, the correspondence with the generalized HDE was also established for the quintessence and for the Ricci DE model. In all the above cases, the effective equation of state (EoS) parameter corresponding to the holographic energy density was determined, by which the equivalence of various DE models with the respective generalized HDE models was further confirmed. The equivalent holographic cut-offs were determined by two ways: (1) in terms of the particle horizon and its derivatives, (2) in terms of the future horizon horizon and its derivatives.

Three Attitudes Toward Astrology: Rabelais, Montaigne, and Pontus de Tyard

PMLA ◽  
1949 ◽  
Vol 64 (3) ◽  
pp. 530-548 ◽  
Author(s):  
John C. Lapp
Keyword(s):  
Free Will ◽  
The Other ◽  
Other Hand ◽  
The People ◽  
The Future ◽  
The Mind ◽  
The Universe ◽  
The Church

Burckhardt has remarked that during the Renaissance culture and enlightenment were almost powerless against astrology, kept alive as it was by the ardent imagination of the people, and their passionate wish to penetrate the future. But what he calls the “delusion” of astral influence charmed even the cultured and enlightened, and for rather more complex reasons than he suggests. The modern scholar, in analyzing Renaissance trends, tends to denounce the mind that surrenders to such influences in a rationalist atmosphere. A belief in the occult powers of the stars over Man did not, however, necessarily betray intellectual backwardness, nor was disbelief a proof of great enlightenment. Astrology, though often tolerated by princes of the Church, generally incurred the censure of theologians, and such a fatalistic belief, denying free will and granting powers of revelation to stars named for pagan dieties, appeared to the clerical mind as an incitement to idolatry. In many cases, then, the opponents of the art were conformists, not rebels—nor were they immune to superstition. Even so formidable an enemy of the stars as Pico della Mirandola toyed with magic and the cabala, and often directed his attack at science in general. On the other hand, such a champion of astrology as Mellin de Saint-Gelays argued that Man should remain unhindered in his desire to fathom the mysterious forces of the universe. If man remains earthbound, never lifting eyes or mind heavenward, wrote Mellin, he will sink to a level beneath all earthly creatures instead of becoming their master. For the French poet, prediction by the stars is not the chief purpose of the true astrologer, but a mere accessory of his earthly and heavenly researches. Such a defense of astrology as this stems from a reluctance to forbid any phase of Man's activity in the search for truth, an attitude which, though uncritical, remains consistent with the rationalistic spirit.

scholarly journals CONSTRAINTS ON A NEW ALTERNATIVE MODEL TO DARK ENERGY

2005 ◽  
Vol 14 (09) ◽  
pp. 1495-1506 ◽  
Author(s):  
YUNGUI GONG ◽  
XI-MING CHEN
Keyword(s):  
Dark Energy ◽  
Alternative Model ◽  
Friedmann Equation ◽  
Recent Past ◽  
New Model ◽  
Type Ia Supernova ◽  
The Future ◽  
Type Ia ◽  
Expansion Of The Universe ◽  
The Universe

The recent type Ia supernova data suggest that the Universe is accelerating now and had decelerated in recent past. This may provide the evidence that the standard Friedmann equation needs to be modified. We analyze in detail a new model in the context of modified Friedmann equation using the supernova data published by the High-z Supernova Search Team and the Supernova Cosmology Project. The new model explains recent acceleration and past deceleration. Furthermore, the acceleration of the expansion of the Universe is almost zero in the future.

‘Newness which never perishes’? Schoenberg’s ambivalent reception of Haydn

2010 ◽  
Vol 51 (1-2) ◽  
pp. 215-224
Author(s):  
Alexander Carpenter
Keyword(s):  
The Other ◽  
Major Influence ◽  
Musical Style ◽  
The Past ◽  
Other Hand ◽  
The Future ◽  
Music Tradition

This paper explores Arnold Schoenberg’s curious ambivalence towards Haydn. Schoenberg recognized Haydn as an important figure in the German serious music tradition, but never closely examined or clearly articulated Haydn’s influence and import on his own musical style and ethos, as he did with many other major composers. This paper argues that Schoenberg failed to explicitly recognize Haydn as a major influence because he saw Haydn as he saw himself, namely as a somewhat ungainly, paradoxical figure, with one foot in the past and one in the future. In his voluminous writings on music, Haydn is mentioned by Schoenberg far less frequently than Bach, Mozart, or Beethoven, and his music appears rarely as examples in Schoenberg’s theoretical texts. When Schoenberg does talk about Haydn’s music, he invokes — with tacit negativity — its accessibility, counterpoising it with more recondite music, such as Beethoven’s, or his own. On the other hand, Schoenberg also praises Haydn for his complex, irregular phrasing and harmonic exploration. Haydn thus appears in Schoenberg’s writings as a figure invested with ambivalence: a key member of the First Viennese triumvirate, but at the same time he is curiously phantasmal, and is accorded a peripheral place in Schoenberg’s version of the canon and his own musical genealogy.

Basic Concepts and Definitions of Allergology

2019 ◽  
Author(s):  
Zoran Vrucinic
Keyword(s):  
Immune Reaction ◽  
The Body ◽  
The Other ◽  
Specific Response ◽  
Other Hand ◽  
Medical Vocabulary ◽  
The Future ◽  
Basic Concepts ◽  
Basic Insight ◽  
Insight Into

The future of medicine belongs to immunology and alergology. I tried to not be too wide in description, but on the other hand to mention the most important concepts of alergology to make access to these diseases more understandable, logical and more useful for our patients, that without complex pathophysiology and mechanism of immune reaction,we gain some basic insight into immunological principles. The name allergy to medicine was introduced by Pirquet in 1906, and is of Greek origin (allos-other + ergon-act; different reaction), essentially representing the reaction of an organism to a substance that has already been in contact with it, and manifested as a specific response thatmanifests as either a heightened reaction, a hypersensitivity, or as a reduced reaction immunity. Synonyms for hypersensitivity are: altered reactivity, reaction, hypersensitivity. The word sensitization comes from the Latin (sensibilitas, atis, f.), which means sensibility,sensitivity, and has retained that meaning in medical vocabulary, while in immunology and allergology this term implies the creation of hypersensitivity to an antigen. Antigen comes from the Greek words, anti-anti + genos-genus, the opposite, anti-substance substance that causes the body to produce antibodies.

Cosmological constant

2018 ◽  
Author(s):  
Michael Kachelriess
Keyword(s):  
Dark Energy ◽  
Cosmological Constant ◽  
Accelerated Expansion ◽  
Vacuum Fluctuations ◽  
Present Epoch ◽  
Modify Gravity ◽  
Expansion Of The Universe ◽  
The Universe

The contribution of vacuum fluctuations to the cosmological constant is reconsidered studying the dependence on the used regularisation scheme. Then alternative explanations for the observed accelerated expansion of the universe in the present epoch are introduced which either modify gravity or add a new component of matter, dubbed dark energy. The chapter closes with some comments on attempts to quantise gravity.

Monotheism in Isaiah

2020 ◽  
pp. 218-248
Author(s):  
Matthias Albani
Keyword(s):  
Historical Context ◽  
The Other ◽  
Divine Power ◽  
Crisis Situation ◽  
Catalytic Function ◽  
Other Hand ◽  
The Future ◽  
The One ◽  
Religious Crisis

The monotheistic confession in Isa 40–48 is best understood against the historical context of Israel’s political and religious crisis situation in the final years of Neo-Babylonian rule. According to Deutero-Isaiah, Yhwh is unique and incomparable because he alone truly predicts the “future” (Isa 41:22–29)—currently the triumph of Cyrus—which will lead to Israel’s liberation from Babylonian captivity (Isa 45). This prediction is directed against the Babylonian deities’ claim to possess the power of destiny and the future, predominantly against Bel-Marduk, to whom both Nabonidus and his opponents appeal in their various political assertions regarding Cyrus. According to the Babylonian conviction, Bel-Marduk has the universal divine power, who, on the one hand, directs the course of the stars and thus determines the astral omens and, on the other hand, directs the course of history (cf. Cyrus Cylinder). As an antithesis, however, Deutero-Isaiah proclaims Yhwh as the sovereign divine creator and leader of the courses of the stars in heaven as well as the course of history on earth (Isa 45:12–13). Moreover, the conflict between Nabonidus and the Marduk priesthood over the question of the highest divine power (Sîn versus Marduk) may have had a kind of “catalytic” function in Deutero-Isaiah’s formulation of the monotheistic confession.

scholarly journals Taxonomy of Dark Energy Models

Universe ◽  
2021 ◽  
Vol 7 (6) ◽  
pp. 163
Author(s):  
Verónica Motta ◽  
Miguel A. García-Aspeitia ◽  
Alberto Hernández-Almada ◽  
Juan Magaña ◽  
Tomás Verdugo
Keyword(s):  
Dark Energy ◽  
Cold Dark Matter ◽  
Accelerated Expansion ◽  
Energy Component ◽  
The Past ◽  
Energy Models ◽  
The Status ◽  
Expansion Of The Universe ◽  
The Universe ◽  
Unknown Component

The accelerated expansion of the Universe is one of the main discoveries of the past decades, indicating the presence of an unknown component: the dark energy. Evidence of its presence is being gathered by a succession of observational experiments with increasing precision in its measurements. However, the most accepted model for explaining the dynamic of our Universe, the so-called Lambda cold dark matter, faces several problems related to the nature of such energy component. This has led to a growing exploration of alternative models attempting to solve those drawbacks. In this review, we briefly summarize the characteristics of a (non-exhaustive) list of dark energy models as well as some of the most used cosmological samples. Next, we discuss how to constrain each model’s parameters using observational data. Finally, we summarize the status of dark energy modeling.

scholarly journals ANISOTROPIC COMPACT STARS WITH VARIABLE COSMOLOGICAL CONSTANT

2012 ◽  
Vol 21 (13) ◽  
pp. 1250088 ◽  
Author(s):  
SK. MONOWAR HOSSEIN ◽  
FAROOK RAHAMAN ◽  
JAYANTA NASKAR ◽  
MEHEDI KALAM ◽  
SAIBAL RAY
Keyword(s):  
Dark Energy ◽  
Cosmological Constant ◽  
Compact Star ◽  
Compact Stars ◽  
Radial Dependence ◽  
Regularity Conditions ◽  
Variable Cosmological Constant ◽  
Expansion Of The Universe ◽  
The Universe ◽  
Surface Redshift

Recently, the small value of the cosmological constant and its ability to accelerate the expansion of the universe is of great interest. We discuss the possibility of forming of anisotropic compact stars from this cosmological constant as one of the competent candidates of dark energy. For this purpose, we consider the analytical solution of Krori and Barua metric. We take the radial dependence of cosmological constant and check all the regularity conditions, TOV equations, stability and surface redshift of the compact stars. It has been shown as conclusion that this model is valid for any compact star and we have cited 4U 1820-30 as a specific example of that kind of star.

scholarly journals I.—Notes on the Phylogeny of the Graptolites

1895 ◽  
Vol 2 (12) ◽  
pp. 529-539 ◽  
Author(s):  
H. A. Nicholson ◽  
J. E. Marr
Keyword(s):  
Present State ◽  
The Other ◽  
Other Hand ◽  
The Family ◽  
The Future ◽  
Geological Magazine

Since the remarkable paper by Professor Lapworth “On an Improved Classification of the Rhabdophora” was published in the Geological Magazine for 1873, a great deal of fresh information has been gathered as to these interesting fossils; but the classification given in that paper, though to some extent confessedly artificial, is still generally adhered to. Observations made by the authors in recent years lead them to suppose that that classification will in the future undergo considerable modification; but in the present state of our knowledge it serves a purpose so useful, that it is not our intention to propose any immediate change in it. Our object, on the other hand, is to bring forward certain conclusions which we have independently reached, and which will, we believe, enhance the value of Graptolites to the stratigraphical geologist, and lead to results important to the biologist. Our conclusions are based upon an examination of a large number of forms generally referred to the family Dichograptidæ; but, as we propose very briefly to indicate, they affect the relationships of Graptolites belonging to other families also.

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